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H Rüden

Publications and source records attributed to H Rüden.

At least 163 records · Page 9Linked to original sources
PubMed1988

[Use of UV rays for the disinfection of water. II. Microbiological studies of surface water].

Untreated surface water of a total bacterial count of approximately 10(4) cfu/ml was contaminated additionally with suspensions of E. coli and S. faecium, which contained about 10(6) cfu/ml. At flow rates of 7.2 m3/h, 4.0 m3/h and 2.0 m3/h the survival of bacteria as a function of exposure to radiation was measured with two different U.V.-disinfection units. In surface water, -without an additional contamination -minimum doses of radiation up to 74 mWs/cm2 were necessary to cause a reduction of 99.99% for total bacterial counts and counts of lactose-positive colonies. When suspensions of E. coli or S. faecium were added, a reduction of 99.99% for total bacterial count was attainable with minimum doses up to 71 mWs/cm2. To reduce the number of lactose-positive colonies or the number of D-streptococci to 99.99% a minimum dose up 56 mWs/cm2 or 18 mWs/cm2 was necessary.

Bacteria↗
PubMed1988

[Nitrated polycyclic aromatic hydrocarbons (nitro-PAH) in suspended particles in the atmosphere. 1. Fractionation and analytic detection].

A procedure to determine nitrated polycyclic aromatic hydrocarbons from suspended particulate matter was developed. Depending on the organic amount needed, different prefractionation steps are described, starting from thin layer chromatography and solid phase extraction by a cartouche system for small amounts, reaching over column chromatography to preparative HPLC for extracts corresponding up to 1000m3. Prior to analysis Nitro-PAH were reduced to the corresponding amines by a modified method given by Jäger. After reduction these amines could be trapped selectively by ion change chromatography and eluted as a pure fraction with a mixture of methanol/isopropylamine 1/1. This mixture can be easily evaporated and the sample is redissolved in acetonitrile/water 80/20, buffered at pH 7.2 by 0.1 M Tris-buffer. 20 microliter of that solution is injected in a HPLC system with a reversed phase column (250 x 4 mm, 5 micron) and fluorescence detection. According to the strong fluorescence properties of amino-PAH detection limits of 5-50 pg could be achieved. Thus, depending on the preconcentration factor (up to 100 m3 per 200 microliter) these compounds could be detected in the range from 0.5-5 pg/m3.

Air Pollution↗
PubMed1987

[Polar neutral organic compounds (POCN) in city aerosols. 2. Measuring of emissions from domestic fuel and vehicle exhaust and from immission particles in Berlin (West)].

During April and May 1985, some emission samples from private coal firing (domestic fuel) were taken and were fired with two different kind of coal (bituminous and brown coal). Also, measurements were done under different combustion conditions (low and high concentrations of oxygenium during the combustion process). In June and November 1985, some emission samples from heavy diesel-engines were taken in a special tunnel equipment, at different engine conditions. During September 1985, also suspended particulates in a highway traffic tunnel were taken. All these samples were taken using high volume cascade impactors which give a fractionation of the suspended particulates into different particle sizes, according to their retention behaviour in the human respiratory system. The results of these emission samples and samples in the highway tunnel were compared with prior immission measurements of urban suspended particulates in Berlin-West, during January 1984. The etherextractable organic matter (= EEOM) of the total suspended particulate matter (= TPM) was determined using ultrasonic extraction method. The EEOM was separated into an acidic (= AF), a basic (= BF) and a neutral fraction (= NF) by dissolution in acidic and basic agents. Of the neutral fraction (NF), further separation was done into aliphatic compounds (= AIP), polycyclic aromatic hydrocarbons (= PAH) and polar neutral organic compounds (POCN) by using thin layer chromatography. From the PAH and POCN, single compounds were identified by gas chromatographic analysis with dual capillary collumns and internal standard method. All organic fractions were tested to their mutagenic activity in the Salmonella typhimurium mammalian microsome bioassay by Ames. The following results were gained: the neutral fraction (NF) made the highest part of the EEOM (greater than or equal to 60%) whereas the part of the AF amounted to 10-25% and of the basic fraction (BF) to approximatively 5-20%. Making further separation of the NF, some differences between the emission sources were gained. Now, the AIP amounted to a percentage of ca. 15% of the NF for coal firing emissions and to ca. 20-40% for diesel-emissions and samples in the highway tunnel. The percentages of the PAH and POCN varied in dependence of the combustion conditions on both emission sources and amounted to 20-50% for the PAH and 30-50% for the POCN. The gas chromatographic analysis showed also differences between the two emission sources. So, for coal firing emissions, higher concentrations for phenanthrene, benzo(a)-pyrene and dibenz(a.h)anthracene (for PAH) and 9-fluorenone (for POCN) were gained.(ABSTRACT TRUNCATED AT 400 WORDS)

Aerosols↗
PubMed1987

[An information system for hospital hygiene. III. Exploratory data analysis of the dynamic aspects in the pathogen spectra of patient specimens from two intensive care units at a Berlin university hospital].

For the 18-months period ending June 1986 the computerised database of the institutes of medical microbiology and of hygiene at Berlin Free University showed about 12,200 specimens from 1,236 intensive care patients. In addition to a traditional tabulation of pathogens by site (urine, wound, bronchial secretion and blood) and service (multidisciplinary post-operative, 4,628 isolates and internal medicine, 1,813 isolates) resulting in a time aggregated assessment of the patients at both intensive care units (ICU) the same data were analysed to detect dynamic variations using 3 different approaches: (1) Medians of the sampling time span (STS) from first specimen of the same patient to follow-up specimens were analysed for 8 pathogens. In specimens from the bronchial tract S. aureus, Klebsiella spp., enterococci and P. aeruginosa showed the same sequence of STS-medians at both ICUs. (2) Dynamic modelling of sequential batches of 100 specimens from the bronchial tract using 3RSSH smoothing showed only poor variation in the proportion of E. coli and enterococci, but demonstrated substantial variation in S. aureus and P. aeruginosa. (3) The negative exponential model was used to fit frequency distributions of STS data. The model suggests a STS half life of 8 days before the first P. aeruginosa is reported from specimens of the bronchial tract of patients mostly with respirators. Periodical reporting of these indicators provides quantitative reference and enables the clinician to better relate individual information from his patients to the epidemiological outcome of his unit.

Bacteria↗
PubMed1987

[Vertical flow of germs in a building shaft: physical and microbiological measurements and development of an analogous mathematical model].

The air flow and the concentration of microorganisms have been measured in the stair shaft of a hospital. A diving bell-type of pressure-recording instrument and samplers for the microorganisms (impaction device) were used. With this experimental data the flow rate of microorganisms between the floors of the hospital was calculated. A physical model based on numerical calculations using simplified transport equations is proposed, which would be able to predict the flow field and the distribution of microorganisms in a staircase. The calculations have been executed up to a Reynolds number of 400 when the Schmidt number is 0.5 and 1.0. This numerical method can help to reduce the experimental work, as well as, to investigate unknown transport mechanisms of organic and inorganic substances including microorganisms.

Air Microbiology↗
PubMed1985

[An information system for hospital hygiene. I. Data acquisition, data bank retrieval and presentation of data].

Aiming at efficient control or prevention of hospital infection it is necessary to provide the clinician immediately with his patient's relevant microbiological data, i.e. relative frequency and susceptibility patterns of species. Therefore an information system for acquisition, on-line storage and retrieval of infection control data was developed together with Institut für Krankenhausausbau of Technische Universität Berlin. The output from the database of microbiological isolates is presented in diagrams for easy evaluation by the clinician and produced either on a graphic color display or on a plotter. The system was developed using a database which was set up retrospectively including about 5000 microbiological isolates from about 1000 intensive care patients of a Berlin university hospital from a period of 18 months. The first communication covers input and output of the data processing system by way of examples. Acquisition of isolates is facilitated at a display terminal using a program to check the data entry and to store the correct data record in a multiple index key oriented file system. Retrieval may be defined either selectively by means of keys, i.e. code of species, specimen or patient entry number or searching across the whole file and for given time periods. One may determine as well to retrieve only data records including test results from selected antibiotics.

Anti-Bacterial Agents↗
PubMed1985

[An information system for hospital hygiene. II. Germ spectrum and resistance representation--an example of use in 2 intensive care units].

By examples it is shown, that there are various possibilities to evaluate the 5380 microbiological findings of patients. 87 different species were isolated and out of these the most frequent species were determined (S. aureus, coagulase-negative staphylococci, D-streptococci, E. cloacae, E. coli, K. pneumoniae, P. mirabilis and P. aeruginosa). By different graphical manners of representation it is shown, how often (absolute and relative) this spectrum of germs occurred within selected periods. The most frequent sampling spots were bronchial and tracheal secretion with a part of 45% and belonging to these sampling spots the spectrum of germs is shown as an example. The recorded findings are appointed to 1020 patients. The possibility of control individual patients by data processing is demonstrated. As examples susceptibility patterns of three species (S. aureus, E. coli and P. aeruginosa) are shown by different manners of representation--spread of resistant strains to several antibiotics, percentage of resistant strains in a certain period and finally a combination of these manners.

Anti-Bacterial Agents↗
PubMed1985

[Polar neutral organic compounds in urban aerosols. 1. Chemical characterization and mutagenic effect in relation to various sources].

Airborne particulate matter was collected by high volume samplers at two sampling stations in Berlin (West) between March 1983 and February 1984 (immissions). The stations were choosen so that two main-sources of urban air pollution could be considered (automobile) traffic and private fuel combustion (domesticfuel). Also in February and March 1983 particles were collected from private coal firing (emissions). The collected particles were fractionated into the following particle sizes (immissions, during October 1983-February 1984): greater than 7.2 microns, 7.2-1.5 microns and less than 1.5 micron (aerodynamic diameter). The etherextractable organic matter of the particles (= EEOM) was determined and the organic matter was then separated into acidic, basic, and neutral fractions. The neutral fraction was further separated into aliphatic compounds (= AlP), polycyclic aromatic hydrocarbons (= PAH), and polar neutral compounds (= POCN) by thin layer chromatography. The mutagenic activity of all organic fractions was determined by using the mammalian microsome bioassay by Ames and was compared with the activity of a whole polar organic extract (including POCN, acidic and basic fraction), a whole neutral extract, and a whole ethersoluble organic extract. Also in February 1984 the nitroreductase specific mutagenicity on immission-stations was determined using nitroreductase deficient strains. Some compounds of the POCN-fraction, and of PAH (in comparison) were identified by gas chromatography. The following results were obtained: The neutral fraction of the organic matter amounted to 70-90% of the EEOM (not depending from particle size, immissions and emissions). The separation of the neutral compounds into AlP, PAH and POCN showed a higher amount of AlP at the collecting station which includes mainly automobile traffic. Some cancer and/or mutagenic suspect compounds were identified by the chromatographic analysis of POCN and PAH. A higher amount of several nitrogroups-containing POCN was found at the collecting station which includes mainly private combustion whereas at the station including mainly automobile traffic 1-nitropyrene was the main compound. The POCN-fraction showed the mostly highest mutagenic activity in the Ames bioassay, mainly for lung penetrating particles (less than 1.5 micron diameter). The whole organic extract (EEOM) showed a lower mutagenic activity than the POCN-fraction. Using nitroreductase deficient strains, at the collecting station which includes mainly private fuel combustion a higher reduction of mutagenicity was shown than at the automobile-traffic including measurement station.

Aerosols↗
PubMed1983

[Mutagenicity of 3 organic fractions of atmospheric dust and gas chromatographic analysis of the basic fraction].

Suspended particulate matter (PM) with a Dae less than 0.4 micron was collected from July 1981 till January 1982. The ether/benzene soluble extract (EEOM) and the acidic, basic and neutral fractions were determined and investigated for their mutagenic activities in the Ames bioassay. In addition particles (Dae) less than 10.2 micron derived in January were investigated. Five compounds of the basic fraction were determined by gaschromatography. The following results were obtained: Suspended particulate matter (Dae less than 0.4 micron) and the ether/benzene extract increase from July to January. The lowest rates occur in July (PM: 16.9 micron/m3) and August (EEOM: 3.0 micrograms/m3), the highest in January (PM: 48.9 micrograms/m3, EEOM: 10.5 micrograms/m3). The ether/benzene soluble portion of the suspended particulate matter increases from the average rate of 16.3% (July-September) to 22.7% (November-January). The neutral fraction amounts to 44.9%, the acidic fraction to 27.3% and the basic fraction to 3.5% of the organic matter (on an average). In experiments with metabolic activation 99% of the total mutagenicity during the period of July till September can be demonstrated by summing up the mutagenicity of the three fractions on the other hand only 59.7% from November till January. The EEOMs derived from winter exhibit without metabolic activation (250 micrograms/plate) distinctively higher numbers of revertants than the single fractions. Dose-response curves of extracts derived from back-up filters (Dae less than 0.4 micron) in January show that the acidic fraction has a slightly higher mutagenic activity than the neutral fraction (mean values of tests with and without S9-mix). The basic fraction shows no mutagenicity without S9-mix, with activation the mutagenic activity is lower than that of the other fractions. Mutagenicity expressed as rev./m3 air shows, that the neutral fraction is most efficient. The number of revertants per plate reveals-in relation to the particle size-different results concerning the three fractions (January).

Acridines↗
PubMed1983

[Measurements of iron, lead, arsenic and selenium concentration in respirable and nonrespirable fractions of Berlin urban aerosols].

In the scope of air quality determinations in the city of Berlin, size fractioned immission concentrations of the heavy metals iron, lead and cadmium and the metalloids arsenic and selenium in suspended particulate matter in air were determined at a highly polluted urban site. The samples were gathered from Juli until December 1981 with a 6-stage-plus-backup high-volume cascade impactor, extracted with 33% HNO3 and analyzed with atomic absorption photometry (AAS) (flame: iron and lead, hydride system: arsenic and selenium) and inductively coupled plasm spectroscopy (ICP) (cadmium). The results show, that - the applied sampling and analyzing procedure proved to be suitable, - the immission concentrations of suspended particulate matter less than 10 micron in Berlin are comparatively high, with values up to 295 ng/m3, - the immission concentrations of the selected trace elements in suspended particulate matter less than 10 micron in Berlin are comparatively low for an industrialized area like this city (Fe: 1280 ng/m3, Pb: 325 ng/m3, Cd: 3.74 ng/m3, As: 11.9 ng/m3, Se: 1.6 ng/m3), but increase markedly during periods of air stagnation as they are quite common in the Berlin winter season (Fe: 2970 ng/m3, Pb: 859 ng/m3, Cd: 8.26 ng/m3, As: 67.3 ng/m3, Se: 6.68 ng/m3), - lead, cadmium, arsenic and selenium of main environmental hygienic interest were concentrated on particles smaller than 2 micron.

Air Pollutants↗
PubMed1983

[Filamentous bacteria in activated sludge (bulking sludge). I. Occurrence of filamentous bacteria in a sewage treatment plant working with the activated sludge process (plug flow system)].

The occurrence of filamentous bacteria in activated sludge (bulking sludge) was investigated in the sewage treatment plant Berlin-Ruhleben. The studies were carried out in five periods from 26.10.1981 to 29.7.1982 (= 112 sampling days). It was noticed that filamentous bacteria appeared in the aeration tanks in different quantities and several kinds of species. With the identification key from Eikelboom Microthrix parvicella, Type 021 N and Type 0041 were frequently identified in all aeration tanks, whereas Type 0961 and Nocardia spec. were observed only in several aeration tanks. Haliscomenobacter hydrossis, Thiothrix spec., Type 0914, Type 1701, Type 1851 and Type 1852 appeared only sporadically. Besides the familiar filamentous bacteria another species was identified under the microscope which, however, could not be classified so far. The filaments are straight or slightly bent with a visible septation and long cylindrical cells. The species is Gram- and Neisser-negative and shows no deposition of sulfur granules.

Bacteria↗
PubMed1983

[Microbial contamination of hospital waste].

Hospital wastes from a surgical department (operating unit, intensive care unit, nursery) and household refuse were examined with respect to their bacterial concentrations and species' pattern. The waste samples were processed by active suspending - a new method in the field of waste examination - which allowed gentle homogenization and quantitative microbial counts. Among several established features the most relevant ones like bacterial concentration and relative frequency of bacterial groups (aerobic bacteria, (facultative) anaerobic bacteria, gramnegative bacteria and D-streptococci) indicated, that hospital wastes were not more contaminated than household refuse. Under this aspect, the present practice of hospital waste management, whose main concern is the spread of infectious agents outside the hospital, deserves a reevaluation.

Bacteria↗